1. Field of the Invention
This invention relates to deadbolt locksets. More particularly, the invention relates to deadbolt locksets in which the backset is adjustable prior to installation.
2. Description of the Prior Art
Deadbolt locksets typically have a backset of two and three eighths inches or two and three quarters inches. The backset is the distance from the edge of the door to the axis of the actuating knob. When a deadbolt lockset is to be replaced, a new lockset having the same backset must be used. Adjustable locksets alleviate the problem of determining which size to use, and also allow for smaller inventories.
The throw of a bolt is defined as the distance the bolt travels from its retracted portion to its extended position, or the distance the bolt extends out of the bolt housing when the bolt is in its extended position. In some applications, an extra length of throW is required. As an example, a deadbolt lockset may be mounted in a pair of doors, where the bolt must travel out of one door and into the other in order to lock both doors. The bolt may also have to pass through a partition between the two doors. It is important that the total throw of the bolt be maintained, regardless of the selected backset.
Several types of adjustable deadbolt locksets have been used in the past. Some of these prior art devices are difficult to adjust, and some are very complicated and expensive. For a deadbolt lockset to be commercially acceptable, the lockset must be inexpensive and the backset easy to adjust.